Dynamo-electric machine.



510.846.422 v PATBNTED MAR. 5. 1907. B. OBLSOHLAGER. DYNAMO ELECTRIC MACHINE.

APPLICATION FILED DEC.10,1904.

. 2 SHEETS-SHEET l.

No. 846,422. PATENTED MAR. 5, 1907.

- E. OBLSGHLAGBR.

DYNAMO ELECTRIC MACHINE.

APPLIOATION FILED DEO.10.1904.

2 SHEETSSHBBT 2 7 may [ED STATES PATET @hliii) LSCHLAGER OF: ClIARLOTTENBURG, GERMANY, ASSIGNOR TO SIEMENSSCHUCKERT \Vl-IRKE, GESELLSCHAFT- MIT BESCHRQQT HAFTUNG, OF BERLlN, GERMANY, ACORPORATION OF GERMAN DYNAMQ-ELEOTWC Macrame.

Specification of Letters Patent.

Patented March 5, 1907,

Application filed December 10, 1904. Serial No. 236.259.

in, Germany, have l l l l the first closing oi the circuit voi small'value, 3

1 because ofth'e great inductance of the cirwit, and requires an appreciable time to attain its normal full value even when all the iron of the magnet-ic'circuit is laminated.

' suiting tardiness the excitation of the ma 2 o chine mi ght be done away with by raising the exciting-pressure by. means of a suitable switch mechanism; but this method involves somewhat 'conipliceted apparatus and is unreliable in operation.

According to the present invention the voltagfe available for excitation is arranged to be higher time is necessary to provide the normal exciting-current, the excess voltagebe ing taken up by an external resistance of small inductance when the current has reached its steady value. The inductance of the circuit bein thus smaller in pro iortion to the ohmic resistance, taking inth c0nsideration the higher voltage available, the initial 5 exciting-current will be greater, and it will rapidly reach its full value after the excitingcircuit is ompleted or the exciting-voltage applied.

The apparatus 40 of my present invention is especially ada' ted for use in electricahpower plant in w c large masses are to be accelerated quickl or their direction of motion reversed quicl y such, or instance, as electrically-driven re- .5 versiblc rolling-mills, the steering-gear for ships, gun aying' mechanisms, hauling-motors formines, and other mechanisms, the driving of which is effected by means of starting-machines. These starting-machines, as

is well known, are usually employed by including theelectromotor which is to be ls tarted or regulated in the circuit of the sta tingcurrcnt generator, whereupon the voltage of forming the subiect-matter of the starting-machine, T he rethe current gcnerator is varied between Zero and a maximum value, this being effected by varying the excitation of the starting-current generator. T Electromotors which. serve for driving working machines are often driven and regulated by means of these-called startingdynamo machines. These sterting-machines are secondary machines carrying direct cur rent. The motor has its field excited from a separate source; but this armature is connected in series with the armature oi the starting-machine. The change in velocity and in the direction of rotation of the motor and also the starting and stopping is eiiectcd by merely changing the tension or excitation which latter is sep-- o arately excited just as the motor. Such starting-machines lire oi. great advantage when electroinotors have great working capacities and must be started and stopped often, or when their Velocity or their direction of rotation must be ire uently changed. The advantage consistsin t e fact that the regulation of currents having great intensity is effected by means of apparatus carrying current of low intensity only. in such instances, however, it is necessary to rapidly change the intensity of the exciting-current of the starting-machine and, for instance, bring the excitation from its maximum value to zero in a very short time, and immediately after bring it from zero to itsmaxh mum value in the opposite direction by re versing the exciting-current. This, how.- ever, cannot be done in the ordinary machines, because by reason of the high sell induction of the magnet-coils it always takes a comparatively lon time to bring the magnetization up to the desired cgrec.- A measurement ofthis time is expressed by the time-constant T, which is proportional to the self-induction coefficient L -of the circuit divided bythe total resistance oi the circuit-that is to say r 2 L i.

v NV 7 This equation shows that it is possible to change the time either by altering the selfinduction or by altering the resistance of the circuit. I 1

According to the :present invention the 

